Which device is primarily used for measuring intraocular pressure?

The measurement of intraocular pressure, which is crucial in assessing conditions like glaucoma, is primarily conducted using a tonometry device. Tonometry measures the pressure inside the eye by assessing the resistance of the cornea to indentation or by determining the pressure exerted by a fluid. This is essential in routine eye exams and helps in early detection and management of ocular diseases.

The other devices listed serve different purposes. A sphygmomanometer is used to measure blood pressure, not intraocular pressure. An ophthalmoscope is utilized for examining the interior surfaces of the eye, particularly the retina and optic nerve, providing insights into eye health but not pressure measurements. An optometer is designed for determining refractive errors and measuring visual acuity rather than measuring intraocular pressure. Therefore, the tonometry device stands out as the specific and primary tool for measuring intraocular pressure.